The inventive subject matter comprises the impact and fire resistance of polyurethane foam backed panels. Polyurethane foam backed panels are well known primarily for the thermal insulating properties foam brings to a wall or roof panel. Polyurethane foam has been sprayed into the cavities of framed walls and roofs and on top of roof substrates for decades to provide a high quality building insulation.
Polyurethane foam backed panels have also been known to provide some degree of flexural stiffness to a wall assembly. For example: U.S. Pat. No. 3,258,889 (Richard A. Butcher) discloses a structural wall comprised of polyurethane foam bonded to an interior wallboard and to the sides of studs and teaches added stiffness of the framed wall to enable thinner panels and lighter frame members. U.S. Pat. No. 3,641,724 (James Palmer) discloses a wall section comprised of an exterior cover bonded to the sides of stud members by a polyurethane foam that increases the strength of the entire structure. U.S. Pat. No. 4,748,781 & 4,914,883 (Stanley E. Wencley) discloses polyurethane fillets bonding a panel to frame members to provide an increased strength bonded structure. U.S. Pat. No. 5,736,221 (James S. Hardigg, et al) discloses two half panels with each having a face and a web molded to the face's backside and the webs bonded together to provide a panel having bending strength in all directions.
More recently polyurethane foam backed panels with unique frame supported configurations have been shown to produce significant structural qualities. For example US 20120011792 (Dean P. DeWildt et al) discloses a light-framed wall structure, comprised of sheathing attached to studs with a top and bottom plate and spray polyurethane foam in the cavity, has high axial point, lateral and transverse load bearing properties. In U.S. Pat. No. 9,919,499 I (Kenneth R. Kreizinger) disclosed a frame supported foam backed panel having substantial increased load capacity derived from increasing the bonding strength of the polyurethane foam bonded to both a cladding and supporting frame members. In pending US Application 20180202159 I disclosed that individual frame members of a supporting frame are greatly stiffened when polyurethane foam, of a foam backed panel, is bonded to both the top and the sides of frame members, i.e. is both continuous over a frame and in the frame's cavity.
However, no prior art teaches or even suggests that polyurethane foam can also greatly increase the impact resistance of a cladding or sheathing to which it is bonded to create a foam backed panel. In addition, no prior art teaches or even suggests fire resistant structural configurations for polyurethane foam backed panels. Finally, no prior art teaches a polyurethane foam backed sandwich panel with an insulating refractory core material and polyurethane foam as one of the panel's skin.
As such, one problem to be solved by this inventive matter is the use of polyurethane foam backing to increase a foam backed panel's impact resistance. A second problem to be solved is improving the fire resistance of polyurethane foam backed panels, since foam melts at a relatively low temperature, and thereby limits the foam's usefulness. A third problem to be solved is foam backed panel configurations that prevent polyurethane foam from melting when the face of the panels is subjected to fire.